1. Field of the Invention
The present invention relates to an inhaler which enables its user to inhale fine powders contained in capsules.
2. State of the Art
Many products such as peptides, antihistamines, many types of antibiotics and pharmaceutical substances, herbal, antioxidant and similar substances) are known to be used in the form of fine powders enclosed in capsules generally of elongate form. These products are inhaled by the user using a device (commonly called an inhaler) defining a chamber in which a capsule is housed, to be perforated or broken within this chamber and allow the powder product to escape and be inhaled by the user via a mouthpiece or the like. Various types of inhaler are known, such as those illustrated in U.S. Pat. No. 4,069,819 and in particular in U.S. Pat. No. 4,995,385 and in the corresponding European Patent No. 0 388 621 A1 to which specific reference will be made hereinafter as state of the art.
The inhaler illustrated in U.S. Pat. No. 4,995,385 and EP-B-0388621 has a capsule housing chamber bounded by a main body and by a movable part provided with thin needles or the like which perforate the capsule when the movable part is moved towards and against the capsule. When the movable part is withdrawn, the product in fine powder form contained in the capsule is able to escape through the holes made in it by the needles, its escape being facilitated by the fact that the capsule has dimensions less than those of the chamber in which it is housed, and the fact that in the inhaler, in the lower lateral part of the chamber, there are provided a plurality of windows or apertures with their axis inclined to the axis of the inhaler, in order to transmit to the capsule a rotary movement within the chamber when the user inhales air through the inhaler.
The upper part of the chamber is bounded by a profiled wall comprising a plurality of small holes through which the air inhaled through the inhaler mouthpiece passes, entraining with it the powder which has escaped from the capsule.
The drawback of the aforedescribed inhaler (and of all known inhalers) is the fact that a part of the powder product which has escaped from the capsule deposits on the base of the chamber and about the needles which have perforated the capsule. In this respect, when the inhaler is used, it is held in a substantially vertical position, and the air which is drawn into the chamber through the apertures is unable to remove a part of the powder deposited on the base of the chamber and mix it with the air drawn in.
The main object of the present invention is to provide an inhaler of the aforestated type able to prevent the product in powder form from depositing and collecting on the base of the chamber housing the capsule, such that the entire product in powder form which escapes from the capsule is mixed with the air drawn in by the user.
Another object is to provide an inhaler which is of easy use, of simple structure and of low production cost.
These and further objects are attained by an inhaler for inhaling fine powder contained in capsules of substantially cylindrical shape, comprising an elongate main body, a top part applied to the upper end of the main body and defining therewith a chamber for housing a capsule containing a fine powder to be inhaled, and a movable part guided on the main body and having a portion which projects lowerly from the main body and a portion which has at least one pointed rod extending towards said chamber, the movable part being translatable between an inactive position in which the pointed end of the rod is outside said chamber and an active position in which said end of the rod extends into the chamber in order to perforate a capsule housed therein, in the lower part of the chamber there being provided a plurality of apertures which open to the outside of the peripheral lateral surface of the inhaler, the upper part of the chamber being bounded by a wall which is traversed by a plurality of small holes and is rigid with the top part, the dimensions of the chamber being greater than those of the capsule which it is intended to house, characterised by presenting at least one longitudinal hole which opens at the lower part of said chamber and, respectively, at the lower portion of the movable part to enable air to flow into the chamber from below.
Preferably, said longitudinal hole is rectilinear and is parallel to the axis of translation of the movable part between its inactive and active positions, between the main body and the movable part there acting at least one spring which urges the movable part towards its inactive position.
Again preferably, the chamber for housing the capsule is bounded lowerly by a wall provided with holes for the free passage of said pointed rod and, respectively, for the passage of the air which is drawn into the chamber through said longitudinal hole, said wall which lowerly bounds the chamber being supported by the main body of the inhaler.